The present invention relates to the field of cottonseed processing and more particularly to delinting cottonseed after it has been ginned and before the seed is itself processed to recover oil and other useful byproducts. In greater particularity the present invention relates to improvements in both the efficiency of the delinter and ease of maintenance of the delinter by the operators.
The present invention is an improvement over the delinting apparatus disclosed in U.S. Pat. No. 4,967,448 which is the closest prior art. The '448 patent discloses the basic delinting process and components used in a delinter and its disclosure is incorporated herein by reference in its entirety. As noted in the '448 patent, unprocessed cotton brought from the field to a cotton gin for ginning will produce bales of long cotton fibers while the remaining cottonseed will have a residue of lint thereon. Cottonseed processing apparatus has long been used to remove residue lint from cottonseeds which have already been processed in conventional cotton gins to remove the long, staple fibers from the seeds. The lint removed from the cottonseed is one of the salable products procured from the cotton operation.
Lint is removed in a single pass, called mill run cut lint, or multiple passes through a cottonseed processing apparatus known as a delinter. In multiple pass processes, the first pass lint yields high quality cellulose, used in manufacturing high quality paper. Lint from the second and third passes or mill run cut lint is usually sold in blended form, with munitions lint, hygienic cottonballs and various cellulose based chemicals being common end uses.
It is also desirable to delint seeds to enhance processability for oil extraction. In oil extraction apparatus, lint is a contaminant which detracts from the overall quality of the oil and adds to the maintenance requirements for the oil extraction apparatus.
In the conventional delinter, the lint is continuously removed from seed by subjecting a rotating mass of seed or “seed roll” to a rotating, ganged cylinder of toothed saw blades passing between ribs in a “grate”. The lint is “doffed” from the saw teeth by a revolving brush cylinder.
The seed roll is rotated in a “float chamber” where the seed roll is subjected to the saws. Rotation of the seed roll is caused by a rotating paddle wheel “float” in the center of the seed roll. The density of the seed roll in the float chamber is controlled by a feedback controlled paddle wheel roll feeder upstream of the float. The rotating speed of the roll feeder is determined by the amperage required by the saw cylinder motor, such that seed roll density is maintained at an optimum level for efficient delinting. Typically, however the width of the feeder has been narrower than the width of the saw cylinder, and cottonseed was required to migrate to the ends of the cylinder in an attempt to process the seed through the saw. Rather than flowing smoothly this lateral migration created flow problems as the cottonseed tended to accumulate at the ends of the saw cylinder, resulting in split seeds with a consequent release of oil onto the lint and increased hull content in the lint discharged at both ends of the saw cylinder. Thus, recent delinters such as shown in the '448 patent, which were more energy efficient suffered from decreased quality of lint when operated at energy saving rates.
Machines used for delinting cottonseed are not to be confused with cotton gins which remove the staple fiber from the seed. Delinting apparatus use the seed cotton which has already been ginned and must be further processed to remove the residual lint from the seed. These machines operate year round rather than seasonally when the cotton is harvested and ginned. In use, the saw cylinders wear rapidly and require frequent sharpening, so a convenient means of accessing and removing the saw cylinder is required. Although the '448 patent greatly improved the access of the operator to the saw cylinder, machines built since that disclosure have suffered from significant drawbacks in operator ease of maintenance. Specifically, the prior machines have required multiple steps to remove the saw cylinder for sharpening, an event that occurs as frequently as daily over the operational life of the machine. For example, each time the saw was removed, the operator had to first loosen the tension on the drive belts from the saw motor and the float motor, then remove the belts, which required that he reach across the ends of the spindle of the saw cylinder and float cylinder and across the discharge augers, then open the gratefall with a fluid actuated cylinder sufficiently to hoist the saw cylinder out of the apparatus. No provision was made to break the circuit to the saw motor other than the on/off switch and the hydraulic cylinders used to open the gratefall had no backup to prevent uncontrolled pivoting of the gratefall during the opening process in case of a hydraulic failure. Thus, the prior system, while an improvement over earlier models was still cumbersome and dangerous.
The value or price of lint is determined by the purity of the lint fiber. The higher the foreign matter or “trash” such as broken hulls, kernels, etc. in the lint, the lower the quality. Therefore it is desirable to remove such trash from the lint in the delinter. “Moting”, the removal of trash (“motes”) from the lint, is accomplished by gravity in a moting chamber, where the heavier or more dense motes fall through an upwardly-flowing airstream created pneumatically to carry away the lint. As noted above, the value of both the seed and the lint is diminished if the seed spends too much time on the saw or is too compressed at the end of the saw cylinder such that the seed hull is torn.
Thus, it can be seen that conventional delinting apparatus currently in use suffers from a number of significant drawbacks. A need presently exists for eliminating these drawbacks, to yield delinting machinery which enables higher efficiency delinting and better quality lint than has previously been obtained.